Global Speed Limits in Context
Speed limits vary enormously by country. Converting between mph and km/h lets you instantly understand what a foreign limit means when driving abroad or reading international car reviews.
- 30 mph = 48.3 km/h — typical residential limit
- 60 mph = 96.6 km/h — typical US rural highway
- 70 mph = 112.7 km/h — UK motorway limit
- 100 km/h = 62.1 mph — most European country road limit
- 110 km/h = 68.4 mph — Australian freeway
- 130 km/h = 80.8 mph — German/French/Italian motorway
- No posted limit (Autobahn) — advisory 130 km/h; no maximum in unrestricted sections
How to Convert mph to km/h
The exact conversion factor is 1.609344 — derived from the international definition of the yard and thus the mile.
- mph × 1.609344 = km/h
- km/h × 0.621371 = mph
- Quick mental trick: mph × 1.6 is accurate to 0.6%
- Another trick: mph × 8 ÷ 5 = km/h (same as multiplying by 1.6)
Aviation and Nautical Speed
Aviation uses knots for airspeed and nautical miles per hour for navigation. One nautical mile equals one minute of arc of latitude, making position calculations on a globe much simpler than with land-based miles or kilometers.
- 1 knot = 1 nautical mile/hour = 1.85200 km/h = 1.15078 mph
- Typical commercial airliner cruise: 450–500 knots = 833–926 km/h
- Mach 1 at sea level (20°C): 343 m/s = 1,235 km/h = 667 knots
- A ship traveling at 20 knots = 23 mph = 37 km/h